Vehicles require a transmission to convert rotational forces as well as rotational speeds. The purpose of a vehicle transmission is to transfer the tractive force of a drive unit. The present invention pertains to a method for operating an automatic transmission. In terms of the present invention, all transmissions with automatic gear changers will be addressed under the term automatic transmission and are also described as phase automatic transmissions.
A method is known from DE 100 35 479 A1 for operating an automatic transmission in which shifts are realized in an interlaced manner for the purpose of improving the shift speed of successive upshifts and/or successive downshifts. For this purpose, during each first upshift and/or downshift, a shift element needed for the successive second upshift and/or downshift is prepared during the ongoing first upshift and/or downshift in such a manner that upon realization of a synchronous speed of the ongoing first upshift and/or downshift, the immediate completion of the successive upshift and/or downshift is possible.
Moreover, according to DE 100 35 479 A1, only single shifts are overlapped with each other, which means that each completed first upshift and/or downshift, as well as each successive second upshift and/or downshift, is a single shift between two immediately successive gears.
Especially when the number of gears in automatic transmissions increase and the gear ratio phases between the immediately successive gears decrease, the preparation of shift elements for a second upshift and/or downshift during the first upshift and/or downshift in the sense of overlapped single shifts causes difficulties since the time needed for the preparation of the shift elements for the second upshift and/or downshift during the first upshift and/or downshift is then no longer available.
Proceeding from this, the present invention is based on the problem of creating a new method for operating an automatic transmission. According to the present invention, depending on a gear change, which is to be completed from an actual gear into a nominal gear as first upshift and/or downshift, a multiple shift is preferred over a single shift.